Audi A4 Knock Sensor Issues Drive Repair Costs Higher

Had the same knock sensor issue on my 2010 Audi A6 with the 2.0T engine. The poor performance and check engine light pattern matched your symptoms exactly. The knock sensor connection was corroded, causing erratic readings and increased fuel consumption. A proper diagnosis revealed the wiring harness to the knock sensor had deterioration where it connects to the sensor body. The ECU was getting incorrect detonation readings, forcing it to run rich fuel mixture as a safety measure. The repair involved replacing both the knock sensor and the wiring harness assembly. It was a serious issue that needed immediate attention since running with faulty knock sensor readings can lead to engine damage. The repair required removing some intake components to access the sensor location. After fixing it, the engine ran smoothly again with normal fuel efficiency. The whole repair took about 4 hours of labor. Based on your description, strongly recommend having a certified shop check the knock sensor wiring connections first before replacing components. The symptoms you describe are classic indicators of knock sensor issues in these engines, particularly the combination of rough idle and increased fuel consumption.

Thanks for the detailed explanation of your knock sensor repair. That malfunction indicator problem sounds exactly like what I am experiencing with my A4. The engine knock and rough running is getting worse by the day. Keen to know, do you remember roughly what the total repair cost was? Also, has everything stayed working properly since the fix or have you had any other sensor issues pop up?

Just got the repair done last week actually. The mechanic found a bad connection at the knock sensor plug, which was causing those engine performance issues we discussed. Total bill came to 95 Euro for fixing the wiring connection, much cheaper than replacing the entire sensor unit. The ignition timing is now spot-on and the engine runs perfectly smooth again. Fuel efficiency has returned to normal levels and that annoying check engine light has stayed off. No more poor performance or rough running since the repair. The fix was simpler than expected since it only needed the connector repair rather than a full sensor replacement. Always worth checking the simple stuff first. Regular maintenance helps catch these issues before they cause bigger problems with engine knock or performance. Keep monitoring how it runs, but based on my experience, once the knock sensor connection is properly fixed, these issues typically dont return.

Finally got my A4 sorted last week after your advice. Took it to a different mechanic who actually listened to the symptoms. They found corroded wiring at the knock sensor connection, just like you mentioned. Bill came to 120 Euro total, bit more than yours but still reasonable. The repair took about 2 hours. Such a relief to have the warning light off and normal fuel efficiency back. Engine runs perfectly smooth now, no more rough idle or knocking sounds. What a difference having the right diagnosis makes. Really glad I asked here before spending money on unnecessary parts replacement. Will definitely keep up with regular maintenance checks to avoid similar issues in the future.